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Leica APO 77 (1 Viewer)
- Thread starter yves0071
- Start date
Thanks for your reply,
Front lens can be unscrewed by hand from central tube.
Who know where are the the separating points? I guess it is possible to separe the central tube from the focussing part (possibly at tte central rotating ring for tripod attachment)?
What is the base of theses special tools? screw/unscrew? pull/push?
Thanks in advance and best regards
Yves
Front lens can be unscrewed by hand from central tube.
Who know where are the the separating points? I guess it is possible to separe the central tube from the focussing part (possibly at tte central rotating ring for tripod attachment)?
What is the base of theses special tools? screw/unscrew? pull/push?
Thanks in advance and best regards
Yves
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garymh
Binocular Engineer
Hi,
Yes, it is possible to unscrew the front lens but then special tools made by Leica are needed to open the prism housing and work on the parts inside.
And.............once you unscrew the front lens you let air into the 'scope and it must be refilled with nitrogen.
Send it to Leica for repair.
Yes, it is possible to unscrew the front lens but then special tools made by Leica are needed to open the prism housing and work on the parts inside.
And.............once you unscrew the front lens you let air into the 'scope and it must be refilled with nitrogen.
Send it to Leica for repair.
Rotherbirder
Well-known member
It's madness to attempt your own repairs on a precision optical instrument without the correct tools & facilities. As has already been said, how do you intend to purge the scope with nitrogen even if you do manage to effect a repair? Leave well alone and let Leica take a look at it!
How to open a Leica 77
Hi,
Finally, it is quite easy. No special tool is required.
Initial recommendations: Prepare a clean & dust free place on a table and small baskets/plates to place the part you will remove. Make sure that the dismantled pieces will not roll to ground!
Then;
• Remove the eyepiece.
• Open the extensible sun hood
• Take the grey body of the scope in one hand and the black part with the front lend in other hand, and unscrew) the font lens section (opposite clock wise)
• Then the nitrogen escape !
• Take a long screw driver (cruciform) and unscrew the 4 screws.
• (Tip: Scrub the screwdriver end to a powerful magnet in order to magnetize it. This will help you to remove screw when you will pull up the screw driver.
• Then you can spare the body to the prism casing (pull while turning)
• You will now see deeper in the prism casing, 4 screws (Allen shape). You need now use a long allen screw driver. 2 are easy to unscrew. For the 2 others, you need to introduce the Allen screw driver between the rubber focusing belt and the body, and unscrew. Easy !
• You can now pull and split the prism housing part to the back part (where the eyepiece is attached).
• No need to remove the 4 Allen screws if you are afraid to not be able to put them again in their hole. You can just secure them with a rubber ring on the thread side (as shown on photo)
• You do no need to remove back part if you only need to replace the focusing belt.
• to rebuild it, do theses tasks in opposite way until it remains only the front lens, taking care of greasing the front lens thread and ay ring between elements.
• Now you will need to fill it with nitrogen if you have a nitrogen bottle*.
• Introduce a 30cm plastic pipe deeper in the body and start to gently deliver nitrogen opening bottle tap. Nitrogen will push out air. The front lens is approached to the top, like a pan cover, reducing the entrance.
• Pull up & remove the nitrogen pipe little by little up to the top and direct the pipe to the front lens which you place now just above, ready to screw up
• By screwing up the front lens, a little over pressure will occur and will avoid air/water entering (equivalent to 0.2 or 0.3 atmosphere).
Many of the internal part are glued/sticky. This is specially made to catch any free flying dust.
*If you do not have a nitrogen bottle at home, which is not common (you can do it at a tyre repair/replacement shop and You can ask them to refill the scope. It will just cost few Euros/Pounds (Nitrogen is also used for tyres as it is more stable as molecules are bigger than air, and for sure no fogg as there is no oxygen/hydrogen).
Any question, please ask
Yves
Hi,
Finally, it is quite easy. No special tool is required.
Initial recommendations: Prepare a clean & dust free place on a table and small baskets/plates to place the part you will remove. Make sure that the dismantled pieces will not roll to ground!
Then;
• Remove the eyepiece.
• Open the extensible sun hood
• Take the grey body of the scope in one hand and the black part with the front lend in other hand, and unscrew) the font lens section (opposite clock wise)
• Then the nitrogen escape !
• Take a long screw driver (cruciform) and unscrew the 4 screws.
• (Tip: Scrub the screwdriver end to a powerful magnet in order to magnetize it. This will help you to remove screw when you will pull up the screw driver.
• Then you can spare the body to the prism casing (pull while turning)
• You will now see deeper in the prism casing, 4 screws (Allen shape). You need now use a long allen screw driver. 2 are easy to unscrew. For the 2 others, you need to introduce the Allen screw driver between the rubber focusing belt and the body, and unscrew. Easy !
• You can now pull and split the prism housing part to the back part (where the eyepiece is attached).
• No need to remove the 4 Allen screws if you are afraid to not be able to put them again in their hole. You can just secure them with a rubber ring on the thread side (as shown on photo)
• You do no need to remove back part if you only need to replace the focusing belt.
• to rebuild it, do theses tasks in opposite way until it remains only the front lens, taking care of greasing the front lens thread and ay ring between elements.
• Now you will need to fill it with nitrogen if you have a nitrogen bottle*.
• Introduce a 30cm plastic pipe deeper in the body and start to gently deliver nitrogen opening bottle tap. Nitrogen will push out air. The front lens is approached to the top, like a pan cover, reducing the entrance.
• Pull up & remove the nitrogen pipe little by little up to the top and direct the pipe to the front lens which you place now just above, ready to screw up
• By screwing up the front lens, a little over pressure will occur and will avoid air/water entering (equivalent to 0.2 or 0.3 atmosphere).
Many of the internal part are glued/sticky. This is specially made to catch any free flying dust.
*If you do not have a nitrogen bottle at home, which is not common (you can do it at a tyre repair/replacement shop and You can ask them to refill the scope. It will just cost few Euros/Pounds (Nitrogen is also used for tyres as it is more stable as molecules are bigger than air, and for sure no fogg as there is no oxygen/hydrogen).
Any question, please ask
Yves
Attachments
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Looks like you left everybody speechless! :t:
Thanks for the report, though I still think that's only for very few to do this themselves. Obviously, the scope must also come apart where the tripod attachment ring is. Leica once had to replace mine as the shoe had broken off due to a crash of the scope to the rocks on the ground. But the optical system had survived . Anyway, I had always been curious how that separation is accomplished. So now I know. Thanks so much. :t:
Thanks for the report, though I still think that's only for very few to do this themselves. Obviously, the scope must also come apart where the tripod attachment ring is. Leica once had to replace mine as the shoe had broken off due to a crash of the scope to the rocks on the ground. But the optical system had survived . Anyway, I had always been curious how that separation is accomplished. So now I know. Thanks so much. :t:
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